Let G be some point on the diagonal line away from point E.
Angle DEG represents angle 1.
We're given that angle DEF is a right angle which means it's 90 degrees. Angle DEG is some angle smaller than 90 degrees. By definition, that must mean angle 1 is acute. Any acute angle is smaller than 90 degrees. There's not much else to say other than this is just a definition problem.
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Extra side notes:
If angle 1 was a right angle, then that would mean angle GEF would have to be 0 degrees; however the diagram shows this isn't the case.
If angle 1 was obtuse, then there's no way we'd be able to fit it into angle DEF. In other words, there's no way to have an angle larger than 90 fit in a 90 degree angle.
The equation of the line is y=2/3x + 0
Explanation: The y intercept (where the line crosses the y axis) is 0, and the slope is 2/3 (up two and 3 to the right)
Simple this is a geometric sequence answer is 32 becauase geometric sequences in this term mean a5*2, giving us 32.
It’s volume / designation